Friday, April 21, 2017

How to make, a mini DIY crossbow

This was an experimental build and the design evolved throughout the making process.

I begun by designing my bow’s arches in a piece of plywood. Using carpet tape I glued two pieces of plywood temporarily together.

I then cut those pieces out, on the bandsaw. I used my rasps and sandpaper to finish the shaping. I also drilled the necessary holes using my drill.

I then used a spatula to separate the two pieces. To remove any remaining tape I used my heat gun.

On another piece of plywood, I drew half the body of my bow and cut it out on the bandsaw. I then used it as a template on a piece of cardboard. I flipped the cardboard around and drew the other half of the bow’s body.

Using two dowels, I temporarily placed the bows on the body. I predrilled two pilot holes and screwed two screws with washers in place. These screws will connect the springs with the bows using nylon string.

Following the same procedures, I mounted two springs on the body of my bow. These two springs provide the bow with the force it needs, in order to operate.

Using washers, threaded rod and butterfly nuts I mounted the arches in place. I also added two screws that act as stoppers, to prevent the arches from moving around.

I then added the string, that connects the springs with the two arches.

At the ends of the arches, I added two dowels. I connected them with another piece of nylon string. I secured the string in place, with zip ties.

I then made the front handle using 20mm plywood. I cut the shape out on the bandsaw. Using my rasps I created a chamfer on it’s edges to make it more ergonomical. I glued it in place. I predrilled and countersinked two holes. I secured the handle with two long screws.

I then used the bandsaw, to cut two arrow guides. I glued and nailed them in place.

The back handle slides in place. I also used the bandsaw to cut a piece out in order for it to receive the cock of the trigger. I temporarily added all the pieces of the trigger in place and freehanded the shape of the cock. I used the bandsaw to cut the cock in shape.

I glued a small piece that acts as aiming point. It also keeps the arrow in place.

I glued and screwed the back handle in place. I secured the cock in place using a small nail as pin.

On both sides of the bow’s body, I added two screws. A rubber band is wrapped around the screws and the cock. This mechanism acts as spring to keep the cock down.

The arrow is just a dowel. I cut a groove on it’s edge on the bandsaw in order for the cock to have something to grab onto. I then sharpened the tip of the arrow on the disc sander.

My mini toy crossbow is now ready. Although I did not make it really powerful, it still needs to be treated carefully. If you decide to make one, do not use it against live targets. A piece of cardboard or styrofoam are perfect targets for playing and enjoying the toy with safety.